Descriptions of the first use of chewing gum date back to the ancient Greek, where people used tree resins from the mastic tree to quench thirst or freshen ones breath. The first chewing gum was not successfully marketed until the late 19th century, when the rubbery tree sap of the Sapodilla tree formed the basis of the gum. In the late 20th century, chewing gum is not only regarded as a symbol of life style, but also effects on cognitive performance, mood, alertness and appetite control have been reported. Moreover, chewing gum has developed more towards a oral care and functional food product (“nutriceutical”) as it provides an easily applicable drug delivery vehicle with potential benefits for oral health. High consumption rates, up to 2.5 kg per person per year, have made it into a billion dollar industry.
Generally, chewing gums consist of a water insoluble mixture of synthetic elastomers, like polyvinyl acetate or polyisobutylene, generally referred to as the gum-base. Important requirements to gum-base materials are that they do not dissolve in the mouth and can be chewed for long periods of time without undergoing compositional changes. In all commercially available chewing gums, the gum-base is supplemented with structuring, softening and flavoring agents, while nowadays sugar is frequently replaced by artificial sweeteners such as sorbitol, xylitol or mannitol.
The inclusion of xylitol and other artificial sweeteners has been described to reduce the formation of oral biofilms on teeth. Oral biofilms are causative to the world's most wide-spread infectious diseases, namely caries and periodontal disease. Caries arise from an imbalance between naturally occurring de- and remineralization of dental enamel. Demineralization occurs when the pH of oral biofilm drops below 5.5 due to the fermentation of sugars by selected members of oral biofilms on teeth. Most artificial sugars are not or barely fermented by oral bacteria and therewith do not lower the pH. Moreover, chewing gum yields enhanced mastication that stimulates saliva production, therewith increasing the concentrations of calcium and phosphates in the oral cavity required for remineralization. Fluorides have been added to commercial gums to prevent enamel demineralization and stimulate remineralization. It is tempting to regard the chewing of gum as an addendum to daily oral hygiene procedures, especially since most people have through the ages been unable to maintain a level of oral biofilm control required to prevent disease. This has led to the incorporation of antimicrobials like chlorhexidine and herbal extracts to chewing gums and gums have indeed been demonstrated successful in preventing re-growth of oral biofilm. Although it is known that chewing of gum aids removal of interdental debris (Kakodkar et al. Dental Research Journal 7: 64-69, 2011) and detergents like polyphosphates have been added to gums to increase their cleaning power, it is unclear whether chewing of gum will actually remove bacteria from the oral cavity. Especially the preferential removal of disease causing organisms like acid-producing Streptococcus mutans or species that are regarded as initial colonizers to the dental enamel by chewing gum would turn chewing gum into a valuable addendum to daily oral hygiene procedures.
The human oral cavity contains a varied and vast amount of flora, and many diseases of the gastrointestinal system and respiratory system can manifest in the oral cavity. There are also many diseases that are specific to the oral cavity. In addition to bacterial organisms, oral microorganisms can include fungal, protozoal, and viral species and many of these microorganisms adhere to the teeth, the gingival sulcus, the tongue, and the buccal mucosa. Each site has a unique way of allowing the organisms to establish their residency. Many of these microorganisms may adhere to polymers that they contact while in the oral cavity, and these polymers include dental and periodontal apparatus and compositions in addition to chewing gum as described above.
Therefore, there is a need for the development of new methods to detect, identify and quantify the numbers of microorganisms that adhere to or are entrapped within polymers in the oral cavity, such as bacteria that are trapped into a chewing gum after use.